A classical nova is an eruption on the surface of a white dwarf in an accreting binary system. The material ejected from the white dwarf surface generally forms an axisymmetric shell. The shaping mechanisms of nova shells are probes of the processes that take place at energy scales between planetary nebulae and supernova remnants. We report on the discovery of nova shells surrounding the post-nova systems V4362 Sagittarii (1994) and more limited observations of DO Aquilae (1925). Distance measurements of 0.5p/m1.4 kpc for V4362 Sgr and 6.7 p/m 3.5 kpc -0.2 for DO Aql are found based on the expansion parallax method. The growth rates are measured to be 0.07``/year for DO Aql and 0.32``/year for V4362 Sgr. A preliminary investigation into the ionisation structure of the nova shell associated with V4362 Sgr is presented. The observed ionisation structure of nova shells depends strongly on their morphology and the orientation of the central component towards the observer. X-ray, IR and UV observations as well as optical integral field unit spectroscopy are required to better understand these interesting objects.

中文翻译：

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与 V4362 Sagittarii 和 DO Aquilae 相关的两个新星壳

经典新星是在吸积双星系统中白矮星表面的喷发。从白矮星表面喷出的物质一般形成一个轴对称壳。新星壳的形成机制是对行星状星云和超新星遗迹之间能量尺度上发生的过程的探测。我们报告了围绕后新星系统 V4362 Sagittarii (1994) 和更有限的 DO Aquilae (1925) 观测的新星壳的发现。V4362 Sgr 的距离测量值为 0.5p/m1.4 kpc，DO Aql 的距离测量值为 6.7 p/m 3.5 kpc -0.2 基于扩展视差方法。DO Aql 的增长率为 0.07``/年，V4362 Sgr 的增长率为 0.32``/年。介绍了与 V4362 Sgr 相关的新星壳电离结构的初步研究。观察到的新星壳的电离结构很大程度上取决于它们的形态和中心成分朝向观察者的方向。需要 X 射线、IR 和 UV 观察以及光学积分场单元光谱来更好地了解这些有趣的物体。